Melatonin: My Love-Hate Relationship



I’m a fan of melatonin supplementation, but perhaps not for the reason most people like it. Melatonin is the most-purchased supplement of any natural product, selling over $800 million in annual sales. And most people buying melatonin purchase it for sleep.

I like melatonin for cancer, especially breast cancer. This 2010 peer-reviewed paper details 11 different anti-cancer mechanisms that melatonin provides. For estrogen-positive breast cancers, the tumor needs estrogen to live. Blocking estrogen binding to the tumor is one key strategy for killing it.

Melatonin acts as a Selective Estrogen Receptor Modulator (SERM). Unlike tamoxifen which is also a SERM, melatonin neither binds to the estrogen receptor nor interferes with the binding of estrogens (E2) to its receptor.  Instead, melatonin decreases the expression of estrogen receptors on the estrogen response element (ERE).

Melatonin is also anti-cancerous by helping to reduce the risk of metastasis theoretically by reducing cancer stem cells, which are resistant to chemotherapy.

But melatonin is really a hormone vs a plant-based molecule. And like all hormones, it has a negative feedback loop so that when a certain amount is detected in the blood, its production shuts off.  This is like you turning on your heat to 75°F when it’s 65°F in the house. The thermostat shuts off the heat once it reaches 75°F. 

One of my good friends has his Ph.D. in plant sleep cycles and has long said that he would never take melatonin for sleep. This is because with a biological negative feedback loop, the other molecules that lead up to the last molecule in the loop are also shut off. For the melatonin negative feedback loop, these molecules and the enzymes that convert them are seen in the figure below.

Figure 1.  The Biological Cascade of Melatonin Production

So, when melatonin is high, serotonin and 5-HTP are also shut off. 5-HTP is not only good for sleep, but also helps with mood issues, digestion, and obesity. Serotonin is not only good for sleep, but also helps with memory, pain, and wound healing. 

And melatonin production is naturally around 200 picograms per mL. With five liters of blood in the average body, about 0.001 mg would lead to this blood level. The smallest supplemental dose typically sold is 1 mg, which would no doubt turn off natural production of melatonin. 

But there is a growing number of people who do not like to use melatonin for sleep. 

If you’re one of those or are looking for a non-melatonin sleep-mood supplement, try our SleepElite.  The description of what’s in SleepElite and why they are good for sleep and/or mood can be found here

If you want to try it, today through Sunday it’s on sale with up to a 25% off subscription here.  


2 Comment

Hope: It depends on what you’re using it for. If you use it to block estrogen, then perhaps – check with your clinician. If at night, then chip off a flack from that pill and use the smallest amount.

Curious as to when you recommend to take melatonin? I normally take 20 mg at night, but if during the day is better, I’m open to change. I take it for overall health benefits as opposed as to taking only for sleep.

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